Ian Cheong's invention — an
approach to killing cancer that uses bacteria and
drug-filled molecular capsules — brought him the top
award and a cash prize
of $25,000. Photo by Will Kirk / HIPS

By Vanessa WastaJohns Hopkins Medicine

A postgraduate student at the Johns
Hopkins Kimmel Cancer Center has won top prize in a
national inventors competition for a new combo approach to
killing cancer using bacteria and drug-filled molecular
capsules.

Ian Cheong is the grand prize winner of the 2007
Collegiate Inventors Competition hosted by
the National Inventors Hall of Fame. The award was
announced Nov. 1 at the California Institute of
Technology campus, where Cheong and 10 other finalists
presented their inventions to a panel of eight
judges, including several Hall of Fame inductees. Along
with the award, Cheong will receive a $25,000
cash prize, and $15,000 will go to his adviser, cancer
researcher Bert Vogelstein.

"It's a great way to deliver drug therapies," said
Vogelstein, professor and co-director of the
Ludwig Center at Johns Hopkins and a Howard Hughes Medical
Institute investigator. "The approach
could be used in a variety of targeted therapies for
cancer, and because many drugs can be packaged
this way, it could have general utility."

In designing the molecular package, Cheong's goal was
to find a mode of transport that avoided
healthy cells and delivered cancer-killing chemicals to the
diseased cells alone. His solution was to add
specially packaged chemotherapy to a bacterial attack
against tumors.

"Packaged" cancer drugs currently are available in
microscopic fatty capsules called liposomes,
which gravitate to tumors because they are too large to fit
through the skins of tightly woven blood
vessels surrounding normal tissue and small enough to slide
through tumor vasculature.

Before the chemo packs moved into place within the
tumor, Cheong added genetically modified
bacteria that have a special affinity for the
oxygen-starved core of tumors. The bacteria secrete an
enzyme, which Cheong dubbed liposomase, that melts away the
outer layer of liposomes, releasing
their anticancer contents.

Tests in nearly 100 mice wiped out large and small
tumors and cured more than two-thirds of
them. The report was published in the Nov. 24 issue of
Science.

Cheong says that a laboratory colleague urged him to
enter the competition. "I'm really glad he
encouraged me to compete. It's been an incredible
experience meeting all of the inventors and sharing
my work with them," he said.

Cheong, 33, is a native of Singapore and received his
doctorate in cell and molecular medicine
from the Johns Hopkins University School of Medicine.
Before pursuing a career in cancer research,
Cheong was an attorney in a Singapore law firm, where
working on the technical aspects of some cases,
he says, drew him to the creative aspects of scientific
research. He is completing postdoctoral studies
at the Johns Hopkins Kimmel Cancer Center.

Panelists for the competition made their selections
from more than 100 undergraduate and
graduate applicants enrolled at 70 colleges and
universities across the United States and Canada. In
addition to Cheong's being awarded the grand prize, two
other finalists received cash awards of
$15,000. Sponsors of the competition are the U.S. Patent
and Trademark Office and the Abbott
Fund, the philanthropic arm of Abbott Laboratories.